/******************************************************************************
 * Project:  PROJ.4
 * Purpose:  Internal plumbing for the PROJ.4 library.
 *
 * Author:   Thomas Knudsen, <thokn@sdfe.dk>
 *
 ******************************************************************************
 * Copyright (c) 2016, 2017, Thomas Knudsen / SDFE
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO COORD SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *****************************************************************************/

#ifndef PROJ_INTERNAL_H
#define PROJ_INTERNAL_H

#ifndef __cplusplus
#error "proj_internal.h can only be included from a C++ file"
#endif

#ifdef _MSC_VER
#ifndef _CRT_SECURE_NO_DEPRECATE
#define _CRT_SECURE_NO_DEPRECATE
#endif
#ifndef _CRT_NONSTDC_NO_DEPRECATE
#define _CRT_NONSTDC_NO_DEPRECATE
#endif
#endif

/* enable predefined math constants M_* for MS Visual Studio */
#if defined(_MSC_VER) || defined(_WIN32)
#ifndef _USE_MATH_DEFINES
#define _USE_MATH_DEFINES
#endif
#endif

// Use "PROJ_FALLTHROUGH;" to annotate deliberate fall-through in switches,
// use it analogously to "break;".  The trailing semi-colon is required.
#if !defined(PROJ_FALLTHROUGH) && defined(__has_cpp_attribute)
#if __cplusplus >= 201703L && __has_cpp_attribute(fallthrough)
#define PROJ_FALLTHROUGH [[fallthrough]]
#elif __cplusplus >= 201103L && __has_cpp_attribute(gnu::fallthrough)
#define PROJ_FALLTHROUGH [[gnu::fallthrough]]
#elif __cplusplus >= 201103L && __has_cpp_attribute(clang::fallthrough)
#define PROJ_FALLTHROUGH [[clang::fallthrough]]
#endif
#endif

#ifndef PROJ_FALLTHROUGH
#define PROJ_FALLTHROUGH ((void)0)
#endif

/* standard inclusions */
#include <limits.h>
#include <math.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "proj/common.hpp"
#include "proj/coordinateoperation.hpp"

#include <string>
#include <vector>

#include "proj.h"

#ifdef PROJ_RENAME_SYMBOLS
#include "proj_symbol_rename.h"
#endif

#define STATIC_ASSERT(COND) ((void)sizeof(char[(COND) ? 1 : -1]))

#ifndef PJ_TODEG
#define PJ_TODEG(rad) ((rad)*180.0 / M_PI)
#endif
#ifndef PJ_TORAD
#define PJ_TORAD(deg) ((deg)*M_PI / 180.0)
#endif

/* Maximum latitudinal overshoot accepted */
#define PJ_EPS_LAT 1e-12

#define C_NAMESPACE extern "C"
#define C_NAMESPACE_VAR extern "C"

#ifndef NULL
#define NULL 0
#endif

#ifndef FALSE
#define FALSE 0
#endif

#ifndef TRUE
#define TRUE 1
#endif

#ifndef MAX
#define MIN(a, b) ((a < b) ? a : b)
#define MAX(a, b) ((a > b) ? a : b)
#endif

#ifndef ABS
#define ABS(x) ((x < 0) ? (-1 * (x)) : x)
#endif

/* maximum path/filename */
#ifndef MAX_PATH_FILENAME
#define MAX_PATH_FILENAME 1024
#endif

/* If we still haven't got M_PI*, we rely on our own defines.
 * For example, this is necessary when compiling with gcc and
 * the -ansi flag.
 */
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

#ifndef M_1_PI
#define M_1_PI 0.318309886183790671538
#endif

#ifndef M_PI_2
#define M_PI_2 1.57079632679489661923
#endif

#ifndef M_PI_4
#define M_PI_4 0.78539816339744830962
#endif

#ifndef M_2_PI
#define M_2_PI 0.63661977236758134308
#endif

/* M_SQRT2 might be missing */
#ifndef M_SQRT2
#define M_SQRT2 1.41421356237309504880
#endif

/* some more useful math constants and aliases */
#define M_FORTPI M_PI_4                    /* pi/4 */
#define M_HALFPI M_PI_2                    /* pi/2 */
#define M_PI_HALFPI 4.71238898038468985769 /* 1.5*pi */

#ifndef M_TWOPI
#define M_TWOPI 6.28318530717958647693 /* 2*pi */
#endif

#define M_TWO_D_PI M_2_PI                     /* 2/pi */
#define M_TWOPI_HALFPI 7.85398163397448309616 /* 2.5*pi */

/* maximum tag id length for +init and default files */
#ifndef ID_TAG_MAX
#define ID_TAG_MAX 50
#endif

/* Use WIN32 as a standard windows 32 bit declaration */
#if defined(_WIN32) && !defined(WIN32)
#define WIN32
#endif

#if defined(_WINDOWS) && !defined(WIN32)
#define WIN32
#endif

/* directory delimiter for DOS support */
#ifdef WIN32
#define DIR_CHAR '\\'
#else
#define DIR_CHAR '/'
#endif

enum pj_io_units {
    PJ_IO_UNITS_WHATEVER =
        0, /* Doesn't matter (or depends on pipeline neighbours) */
    PJ_IO_UNITS_CLASSIC = 1,   /* Scaled meters (right), projected system */
    PJ_IO_UNITS_PROJECTED = 2, /* Meters, projected system */
    PJ_IO_UNITS_CARTESIAN = 3, /* Meters, 3D cartesian system */
    PJ_IO_UNITS_RADIANS = 4,   /* Radians */
    PJ_IO_UNITS_DEGREES = 5,   /* Degrees */

};
enum pj_io_units pj_left(PJ *P);
enum pj_io_units pj_right(PJ *P);

PJ_COORD PROJ_DLL proj_coord_error(void);

void proj_context_errno_set(PJ_CONTEXT *ctx, int err);
void PROJ_DLL proj_context_set(PJ *P, PJ_CONTEXT *ctx);
void proj_context_inherit(PJ *parent, PJ *child);

struct projCppContext;
/* not sure why we need to export it, but mingw needs it */
void PROJ_DLL
proj_context_delete_cpp_context(struct projCppContext *cppContext);

bool pj_fwd4d(PJ_COORD &coo, PJ *P);
bool pj_inv4d(PJ_COORD &coo, PJ *P);

PJ_COORD PROJ_DLL pj_approx_2D_trans(PJ *P, PJ_DIRECTION direction,
                                     PJ_COORD coo);
PJ_COORD PROJ_DLL pj_approx_3D_trans(PJ *P, PJ_DIRECTION direction,
                                     PJ_COORD coo);

/* Provision for gettext translatable strings */
#define _(str) (str)

void PROJ_DLL proj_log_error(const PJ *P, const char *fmt, ...);
void proj_log_debug(PJ *P, const char *fmt, ...);
void proj_log_trace(PJ *P, const char *fmt, ...);

void proj_context_log_debug(PJ_CONTEXT *ctx, const char *fmt, ...);

int pj_ellipsoid(PJ *);
void pj_inherit_ellipsoid_def(const PJ *src, PJ *dst);
int pj_calc_ellipsoid_params(PJ *P, double a, double es);

/* Geographical to geocentric latitude - another of the "simple, but useful" */
PJ_COORD pj_geocentric_latitude(const PJ *P, PJ_DIRECTION direction,
                                PJ_COORD coord);

char PROJ_DLL *pj_chomp(char *c);
char PROJ_DLL *pj_shrink(char *c);
size_t pj_trim_argc(char *args);
char **pj_trim_argv(size_t argc, char *args);
char *pj_make_args(size_t argc, char **argv);

typedef struct {
    double r, i;
} COMPLEX;

/* Forward declarations and typedefs for stuff needed inside the PJ object */
struct PJconsts;

union PJ_COORD;
struct geod_geodesic;
struct ARG_list;
struct PJ_REGION_S;
typedef struct PJ_REGION_S PJ_Region;
typedef struct ARG_list paralist; /* parameter list */

#ifndef PROJ_H
typedef struct PJconsts PJ; /* the PJ object herself */
typedef union PJ_COORD PJ_COORD;
#endif

struct PJ_REGION_S {
    double ll_long; /* lower left corner coordinates (radians) */
    double ll_lat;
    double ur_long; /* upper right corner coordinates (radians) */
    double ur_lat;
};

struct PJ_AREA {
    bool bbox_set = false;
    double west_lon_degree = 0;
    double south_lat_degree = 0;
    double east_lon_degree = 0;
    double north_lat_degree = 0;
    std::string name{};
};

/*****************************************************************************

    Some function types that are especially useful when working with PJs

******************************************************************************

PJ_CONSTRUCTOR:

    A function taking a pointer-to-PJ as arg, and returning a pointer-to-PJ.
    Historically called twice: First with a 0 argument, to allocate memory,
    second with the first return value as argument, for actual setup.

PJ_DESTRUCTOR:

    A function taking a pointer-to-PJ and an integer as args, then first
    handling the deallocation of the PJ, afterwards handing the integer over
    to the error reporting subsystem, and finally returning a null pointer in
    support of the "return free (P)" (aka "get the hell out of here") idiom.

PJ_OPERATOR:

    A function taking a reference to a PJ_COORD and a pointer-to-PJ as args,
applying the PJ to the PJ_COORD, and modifying in-place the passed PJ_COORD.

*****************************************************************************/
typedef PJ *(*PJ_CONSTRUCTOR)(PJ *);
typedef PJ *(*PJ_DESTRUCTOR)(PJ *, int);
typedef void (*PJ_OPERATOR)(PJ_COORD &, PJ *);
/****************************************************************************/

/* datum_type values */
#define PJD_UNKNOWN 0
#define PJD_3PARAM 1
#define PJD_7PARAM 2
#define PJD_GRIDSHIFT 3
#define PJD_WGS84 4 /* WGS84 (or anything considered equivalent) */

struct PJCoordOperation {
  public:
    int idxInOriginalList;

    // [min|max][x|y]Src define the bounding box of the area of validity of
    // the transformation, expressed in the source CRS. Except if the source
    // CRS is a geocentric one, in which case the bounding box is defined in
    // a geographic lon,lat CRS (pjSrcGeocentricToLonLat will have to be used
    // on input coordinates in the forward direction)
    double minxSrc = 0.0;
    double minySrc = 0.0;
    double maxxSrc = 0.0;
    double maxySrc = 0.0;

    // [min|max][x|y]Dst define the bounding box of the area of validity of
    // the transformation, expressed in the target CRS. Except if the target
    // CRS is a geocentric one, in which case the bounding box is defined in
    // a geographic lon,lat CRS (pjDstGeocentricToLonLat will have to be used
    // on input coordinates in the inverse direction)
    double minxDst = 0.0;
    double minyDst = 0.0;
    double maxxDst = 0.0;
    double maxyDst = 0.0;

    PJ *pj = nullptr;
    std::string name{};
    double accuracy = -1.0;
    bool isOffshore = false;
    bool isPriorityOp = false;
    bool srcIsLonLatDegree = false;
    bool srcIsLatLonDegree = false;
    bool dstIsLonLatDegree = false;
    bool dstIsLatLonDegree = false;

    // pjSrcGeocentricToLonLat is defined if the source CRS of pj is geocentric
    // and in that case it transforms from those geocentric coordinates to
    // geographic ones in lon, lat order
    PJ *pjSrcGeocentricToLonLat = nullptr;

    // pjDstGeocentricToLonLat is defined if the target CRS of pj is geocentric
    // and in that case it transforms from those geocentric coordinates to
    // geographic ones in lon, lat order
    PJ *pjDstGeocentricToLonLat = nullptr;

    PJCoordOperation(int idxInOriginalListIn, double minxSrcIn,
                     double minySrcIn, double maxxSrcIn, double maxySrcIn,
                     double minxDstIn, double minyDstIn, double maxxDstIn,
                     double maxyDstIn, PJ *pjIn, const std::string &nameIn,
                     double accuracyIn, bool isOffshoreIn,
                     const PJ *pjSrcGeocentricToLonLatIn,
                     const PJ *pjDstGeocentricToLonLatIn);

    PJCoordOperation(const PJCoordOperation &) = delete;

    PJCoordOperation(PJ_CONTEXT *ctx, const PJCoordOperation &other)
        : idxInOriginalList(other.idxInOriginalList), minxSrc(other.minxSrc),
          minySrc(other.minySrc), maxxSrc(other.maxxSrc),
          maxySrc(other.maxySrc), minxDst(other.minxDst),
          minyDst(other.minyDst), maxxDst(other.maxxDst),
          maxyDst(other.maxyDst), pj(proj_clone(ctx, other.pj)),
          name(std::move(other.name)), accuracy(other.accuracy),
          isOffshore(other.isOffshore), isPriorityOp(other.isPriorityOp),
          srcIsLonLatDegree(other.srcIsLonLatDegree),
          srcIsLatLonDegree(other.srcIsLatLonDegree),
          dstIsLonLatDegree(other.dstIsLonLatDegree),
          dstIsLatLonDegree(other.dstIsLatLonDegree),
          pjSrcGeocentricToLonLat(
              other.pjSrcGeocentricToLonLat
                  ? proj_clone(ctx, other.pjSrcGeocentricToLonLat)
                  : nullptr),
          pjDstGeocentricToLonLat(
              other.pjDstGeocentricToLonLat
                  ? proj_clone(ctx, other.pjDstGeocentricToLonLat)
                  : nullptr) {}

    PJCoordOperation(PJCoordOperation &&other)
        : idxInOriginalList(other.idxInOriginalList), minxSrc(other.minxSrc),
          minySrc(other.minySrc), maxxSrc(other.maxxSrc),
          maxySrc(other.maxySrc), minxDst(other.minxDst),
          minyDst(other.minyDst), maxxDst(other.maxxDst),
          maxyDst(other.maxyDst), name(std::move(other.name)),
          accuracy(other.accuracy), isOffshore(other.isOffshore),
          isPriorityOp(other.isPriorityOp),
          srcIsLonLatDegree(other.srcIsLonLatDegree),
          srcIsLatLonDegree(other.srcIsLatLonDegree),
          dstIsLonLatDegree(other.dstIsLonLatDegree),
          dstIsLatLonDegree(other.dstIsLatLonDegree) {
        pj = other.pj;
        other.pj = nullptr;
        pjSrcGeocentricToLonLat = other.pjSrcGeocentricToLonLat;
        other.pjSrcGeocentricToLonLat = nullptr;
        pjDstGeocentricToLonLat = other.pjDstGeocentricToLonLat;
        other.pjDstGeocentricToLonLat = nullptr;
    }

    PJCoordOperation &operator=(const PJCoordOperation &) = delete;

    bool operator==(const PJCoordOperation &other) const {
        return idxInOriginalList == other.idxInOriginalList &&
               minxSrc == other.minxSrc && minySrc == other.minySrc &&
               maxxSrc == other.maxxSrc && maxySrc == other.maxySrc &&
               minxDst == other.minxDst && minyDst == other.minyDst &&
               maxxDst == other.maxxDst && maxyDst == other.maxyDst &&
               name == other.name &&
               proj_is_equivalent_to(pj, other.pj, PJ_COMP_STRICT) &&
               accuracy == other.accuracy && isOffshore == other.isOffshore;
    }

    bool operator!=(const PJCoordOperation &other) const {
        return !(operator==(other));
    }

    ~PJCoordOperation();

    bool isInstantiable() const;

  private:
    static constexpr int INSTANTIABLE_STATUS_UNKNOWN =
        -1; // must be different from 0(=false) and 1(=true)
    mutable int isInstantiableCached = INSTANTIABLE_STATUS_UNKNOWN;
};

enum class TMercAlgo {
    AUTO, // Poder/Engsager if far from central meridian, otherwise
          // Evenden/Snyder
    EVENDEN_SNYDER,
    PODER_ENGSAGER,
};

/* base projection data structure */
struct PJconsts {

    /*************************************************************************************

                         G E N E R A L   P A R A M E T E R   S T R U C T

    **************************************************************************************

        TODO: Need some description here - especially about the thread
    context... This is the struct behind the PJ typedef

    **************************************************************************************/

    PJ_CONTEXT *ctx = nullptr;
    const char *short_name = nullptr; /* From pj_list.h */
    const char *descr = nullptr; /* From pj_list.h or individual PJ_*.c file */
    paralist *params = nullptr;  /* Parameter list */
    char *def_full =
        nullptr; /* Full textual definition (usually 0 - set by proj_pj_info) */
    PJconsts *parent = nullptr; /* Parent PJ of pipeline steps - nullptr if not
                                   a pipeline step */

    /* For debugging / logging purposes */
    char *def_size =
        nullptr; /* Shape and size parameters extracted from params */
    char *def_shape = nullptr;
    char *def_spherification = nullptr;
    char *def_ellps = nullptr;

    struct geod_geodesic *geod = nullptr; /* For geodesic computations */
    void *opaque =
        nullptr;      /* Projection specific parameters, Defined in PJ_*.c */
    int inverted = 0; /* Tell high level API functions to swap inv/fwd */

    /*************************************************************************************

                          F U N C T I O N    P O I N T E R S

    **************************************************************************************

        For projection xxx, these are pointers to functions in the corresponding
        PJ_xxx.c file.

        pj_init() delegates the setup of these to
    pj_projection_specific_setup_xxx(), a name which is currently hidden behind
    the magic curtain of the PROJECTION macro.

    **************************************************************************************/

    PJ_XY (*fwd)(PJ_LP, PJ *) = nullptr;
    PJ_LP (*inv)(PJ_XY, PJ *) = nullptr;
    PJ_XYZ (*fwd3d)(PJ_LPZ, PJ *) = nullptr;
    PJ_LPZ (*inv3d)(PJ_XYZ, PJ *) = nullptr;
    PJ_OPERATOR fwd4d = nullptr;
    PJ_OPERATOR inv4d = nullptr;

    PJ_DESTRUCTOR destructor = nullptr;
    void (*reassign_context)(PJ *, PJ_CONTEXT *) = nullptr;

    /*************************************************************************************

                          E L L I P S O I D     P A R A M E T E R S

    **************************************************************************************

        Despite YAGNI, we add a large number of ellipsoidal shape parameters,
    which are not yet set up in pj_init. They are, however, inexpensive to
    compute, compared to the overall time taken for setting up the complex PJ
    object (cf. e.g. https://en.wikipedia.org/wiki/Angular_eccentricity).

        But during single point projections it will often be a useful thing to
    have these readily available without having to recompute at every pj_fwd /
    pj_inv call.

        With this wide selection, we should be ready for quite a number of
    geodetic algorithms, without having to incur further ABI breakage.

    **************************************************************************************/

    /* The linear parameters */

    double a = 0.0;  /* semimajor axis (radius if eccentricity==0) */
    double b = 0.0;  /* semiminor axis */
    double ra = 0.0; /* 1/a */
    double rb = 0.0; /* 1/b */

    /* The eccentricities */

    double alpha = 0.0;   /* angular eccentricity */
    double e = 0.0;       /* first  eccentricity */
    double es = 0.0;      /* first  eccentricity squared */
    double e2 = 0.0;      /* second eccentricity */
    double e2s = 0.0;     /* second eccentricity squared */
    double e3 = 0.0;      /* third  eccentricity */
    double e3s = 0.0;     /* third  eccentricity squared */
    double one_es = 0.0;  /* 1 - e^2 */
    double rone_es = 0.0; /* 1/one_es */

    /* The flattenings */
    double f = 0.0;   /* first  flattening */
    double f2 = 0.0;  /* second flattening */
    double n = 0.0;   /* third  flattening */
    double rf = 0.0;  /* 1/f  */
    double rf2 = 0.0; /* 1/f2 */
    double rn = 0.0;  /* 1/n  */

    /* This one's for GRS80 */
    double J = 0.0; /* "Dynamic form factor" */

    double es_orig = 0.0; /* es and a before any +proj related adjustment */
    double a_orig = 0.0;

    /*************************************************************************************

                          C O O R D I N A T E   H A N D L I N G

    **************************************************************************************/

    int over = 0;       /* Over-range flag */
    int geoc = 0;       /* Geocentric latitude flag */
    int is_latlong = 0; /* proj=latlong ... not really a projection at all */
    int is_geocent = 0; /* proj=geocent ... not really a projection at all */
    int need_ellps = 0; /* 0 for operations that are purely cartesian */
    int skip_fwd_prepare = 0;
    int skip_fwd_finalize = 0;
    int skip_inv_prepare = 0;
    int skip_inv_finalize = 0;

    enum pj_io_units left =
        PJ_IO_UNITS_WHATEVER; /* Flags for input/output coordinate types */
    enum pj_io_units right = PJ_IO_UNITS_WHATEVER;

    /* These PJs are used for implementing cs2cs style coordinate handling in
     * the 4D API */
    PJ *axisswap = nullptr;
    PJ *cart = nullptr;
    PJ *cart_wgs84 = nullptr;
    PJ *helmert = nullptr;
    PJ *hgridshift = nullptr;
    PJ *vgridshift = nullptr;

    /*************************************************************************************

                       C A R T O G R A P H I C       O F F S E T S

    **************************************************************************************/

    double lam0 = 0.0; /* central meridian */
    double phi0 = 0.0; /* central parallel */
    double x0 = 0.0;   /* false easting */
    double y0 = 0.0;   /* false northing  */
    double z0 = 0.0;   /* height origin */
    double t0 = 0.0;   /* time origin */

    /*************************************************************************************

                                    S C A L I N G

    **************************************************************************************/

    double k0 = 0.0; /* General scaling factor - e.g. the 0.9996 of UTM */
    double to_meter = 0.0,
           fr_meter = 0.0; /* Plane coordinate scaling. Internal unit [m] */
    double vto_meter = 0.0,
           vfr_meter = 0.0; /* Vertical scaling. Internal unit [m] */

    /*************************************************************************************

                  D A T U M S   A N D   H E I G H T   S Y S T E M S

    **************************************************************************************

        It may be possible, and meaningful, to move the list parts of this up to
    the PJ_CONTEXT level.

    **************************************************************************************/

    int datum_type =
        PJD_UNKNOWN; /* PJD_UNKNOWN/3PARAM/7PARAM/GRIDSHIFT/WGS84 */
    double datum_params[7] = {0, 0, 0, 0,
                              0, 0, 0}; /* Parameters for 3PARAM and 7PARAM */

    int has_geoid_vgrids = 0;      /* used by legacy transform.cpp */
    void *hgrids_legacy = nullptr; /* used by legacy transform.cpp. Is a pointer
                                      to a ListOfHGrids* */
    void *vgrids_legacy = nullptr; /* used by legacy transform.cpp. Is a pointer
                                      to a ListOfVGrids* */

    double from_greenwich = 0.0;   /* prime meridian offset (in radians) */
    double long_wrap_center = 0.0; /* 0.0 for -180 to 180, actually in radians*/
    int is_long_wrap_set = 0;
    char axis[4] = {0, 0, 0, 0}; /* Axis order, pj_transform/pj_adjust_axis */

    /*************************************************************************************
     ISO-19111 interface
    **************************************************************************************/

    NS_PROJ::util::BaseObjectPtr iso_obj{};
    bool iso_obj_is_coordinate_operation = false;
    double coordinateEpoch = 0;
    bool hasCoordinateEpoch = false;

    // cached results
    mutable std::string lastWKT{};
    mutable std::string lastPROJString{};
    mutable std::string lastJSONString{};
    mutable bool gridsNeededAsked = false;
    mutable std::vector<NS_PROJ::operation::GridDescription> gridsNeeded{};

    // cache pj_get_type() result to help for repeated calls to proj_factors()
    mutable PJ_TYPE type = PJ_TYPE_UNKNOWN;

    /*************************************************************************************
     proj_create_crs_to_crs() alternative coordinate operations
    **************************************************************************************/
    std::vector<PJCoordOperation> alternativeCoordinateOperations{};
    int iCurCoordOp = -1;
    bool errorIfBestTransformationNotAvailable = false;
    bool warnIfBestTransformationNotAvailable =
        true; /* to remove in PROJ 10? */
    bool skipNonInstantiable = true;

    /*************************************************************************************

                 E N D   O F    G E N E R A L   P A R A M E T E R   S T R U C T

    **************************************************************************************/

    PJconsts();
    PJconsts(const PJconsts &) = delete;
    PJconsts &operator=(const PJconsts &) = delete;
};

/* Parameter list (a copy of the +proj=... etc. parameters) */
struct ARG_list {
    paralist *next;
    char used;
#if (defined(__GNUC__) && __GNUC__ >= 8) ||                                    \
    (defined(__clang__) && __clang_major__ >= 9)
    char param[]; /* variable-length member */
    /* Safer to use [] for gcc 8. See https://github.com/OSGeo/proj.4/pull/1087
     */
    /* and https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86914 */
#else
    char param[1]; /* variable-length member */
#endif
};

typedef union {
    double f;
    int i;
    char *s;
} PROJVALUE;

struct PJ_DATUMS {
    const char *id;         /* datum keyword */
    const char *defn;       /* ie. "to_wgs84=..." */
    const char *ellipse_id; /* ie from ellipse table */
    const char *comments;   /* EPSG code, etc */
};

struct DERIVS {
    double x_l, x_p; /* derivatives of x for lambda-phi */
    double y_l, y_p; /* derivatives of y for lambda-phi */
};

struct FACTORS {
    struct DERIVS der;
    double h, k;          /* meridional, parallel scales */
    double omega, thetap; /* angular distortion, theta prime */
    double conv;          /* convergence */
    double s;             /* areal scale factor */
    double a, b;          /* max-min scale error */
    int code;             /* always 0 */
};

// Legacy
struct projFileAPI_t;

struct projCppContext;

struct projNetworkCallbacksAndData {
    bool enabled = false;
    proj_network_open_cbk_type open = nullptr;
    proj_network_close_cbk_type close = nullptr;
    proj_network_get_header_value_cbk_type get_header_value = nullptr;
    proj_network_read_range_type read_range = nullptr;
    void *user_data = nullptr;
};

struct projGridChunkCache {
    bool enabled = true;
    std::string filename{};
    long long max_size = 300 * 1024 * 1024;
    int ttl = 86400; // 1 day
};

struct projFileApiCallbackAndData {
    PROJ_FILE_HANDLE *(*open_cbk)(PJ_CONTEXT *ctx, const char *filename,
                                  PROJ_OPEN_ACCESS access,
                                  void *user_data) = nullptr;
    size_t (*read_cbk)(PJ_CONTEXT *ctx, PROJ_FILE_HANDLE *, void *buffer,
                       size_t size, void *user_data) = nullptr;
    size_t (*write_cbk)(PJ_CONTEXT *ctx, PROJ_FILE_HANDLE *, const void *buffer,
                        size_t size, void *user_data) = nullptr;
    int (*seek_cbk)(PJ_CONTEXT *ctx, PROJ_FILE_HANDLE *, long long offset,
                    int whence, void *user_data) = nullptr;
    unsigned long long (*tell_cbk)(PJ_CONTEXT *ctx, PROJ_FILE_HANDLE *,
                                   void *user_data) = nullptr;
    void (*close_cbk)(PJ_CONTEXT *ctx, PROJ_FILE_HANDLE *,
                      void *user_data) = nullptr;

    int (*exists_cbk)(PJ_CONTEXT *ctx, const char *filename,
                      void *user_data) = nullptr;
    int (*mkdir_cbk)(PJ_CONTEXT *ctx, const char *filename,
                     void *user_data) = nullptr;
    int (*unlink_cbk)(PJ_CONTEXT *ctx, const char *filename,
                      void *user_data) = nullptr;
    int (*rename_cbk)(PJ_CONTEXT *ctx, const char *oldPath, const char *newPath,
                      void *user_data) = nullptr;

    void *user_data = nullptr;
};

/* proj thread context */
struct pj_ctx {
    std::string lastFullErrorMessage{}; // used by proj_context_errno_string
    int last_errno = 0;
    int debug_level = PJ_LOG_ERROR;
    bool errorIfBestTransformationNotAvailableDefault = false;
    bool warnIfBestTransformationNotAvailableDefault = true;
    void (*logger)(void *, int, const char *) = nullptr;
    void *logger_app_data = nullptr;
    struct projCppContext *cpp_context =
        nullptr;                   /* internal context for C++ code */
    int use_proj4_init_rules = -1; /* -1 = unknown, 0 = no, 1 = yes */
    bool forceOver = false;
    int epsg_file_exists = -1; /* -1 = unknown, 0 = no, 1 = yes */

    std::string
        env_var_proj_data{}; // content of PROJ_DATA (or legacy PROJ_LIB)
                             // environment variable. Use
                             // Filemanager::getProjDataEnvVar() to access
    std::vector<std::string> search_paths{};
    const char **c_compat_paths = nullptr; // same, but for projinfo usage

    const char *(*file_finder)(PJ_CONTEXT *, const char *,
                               void *user_data) = nullptr;
    void *file_finder_user_data = nullptr;

    bool defer_grid_opening = false; // set transiently by pj_obj_create()

    projFileApiCallbackAndData fileApi{};
    std::string custom_sqlite3_vfs_name{};
    std::string user_writable_directory{};

    // BEGIN ini file settings
    bool iniFileLoaded = false;
    std::string endpoint{};
    projNetworkCallbacksAndData networking{};
    std::string ca_bundle_path{};
    projGridChunkCache gridChunkCache{};
    TMercAlgo defaultTmercAlgo =
        TMercAlgo::PODER_ENGSAGER; // can be overridden by content of proj.ini
    // END ini file settings

    int projStringParserCreateFromPROJStringRecursionCounter =
        0; // to avoid potential infinite recursion in
           // PROJStringParser::createFromPROJString()
    int pipelineInitRecursiongCounter =
        0; // to avoid potential infinite recursion in pipeline.cpp

    pj_ctx() = default;
    pj_ctx(const pj_ctx &);
    ~pj_ctx();

    pj_ctx &operator=(const pj_ctx &) = delete;

    projCppContext *get_cpp_context();
    void set_search_paths(const std::vector<std::string> &search_paths_in);
    void set_ca_bundle_path(const std::string &ca_bundle_path_in);

    static pj_ctx createDefault();
};

#ifdef PJ_LIB_
#define PROJ_HEAD(name, desc) static const char des_##name[] = desc

#define OPERATION(name, NEED_ELLPS)                                            \
                                                                               \
    pj_projection_specific_setup_##name(PJ *P);                                \
    C_NAMESPACE PJ *pj_##name(PJ *P);                                          \
                                                                               \
    C_NAMESPACE_VAR const char *const pj_s_##name = des_##name;                \
                                                                               \
    C_NAMESPACE PJ *pj_##name(PJ *P) {                                         \
        if (P)                                                                 \
            return pj_projection_specific_setup_##name(P);                     \
        P = pj_new();                                                          \
        if (nullptr == P)                                                      \
            return nullptr;                                                    \
        P->short_name = #name;                                                 \
        P->descr = des_##name;                                                 \
        P->need_ellps = NEED_ELLPS;                                            \
        P->left = PJ_IO_UNITS_RADIANS;                                         \
        P->right = PJ_IO_UNITS_CLASSIC;                                        \
        return P;                                                              \
    }                                                                          \
                                                                               \
    PJ *pj_projection_specific_setup_##name(PJ *P)

/* In ISO19000 lingo, an operation is either a conversion or a transformation */
#define CONVERSION(name, need_ellps) OPERATION(name, need_ellps)
#define TRANSFORMATION(name, need_ellps) OPERATION(name, need_ellps)

/* In PROJ.4 a projection is a conversion taking angular input and giving scaled
 * linear output */
#define PROJECTION(name) CONVERSION(name, 1)

#endif /* def PJ_LIB_ */

/* procedure prototypes */
double PROJ_DLL dmstor(const char *, char **);
double dmstor_ctx(PJ_CONTEXT *ctx, const char *, char **);
void PROJ_DLL set_rtodms(int, int);
char PROJ_DLL *rtodms(char *, size_t, double, int, int);
double PROJ_DLL adjlon(double);
double aacos(PJ_CONTEXT *, double);
double aasin(PJ_CONTEXT *, double);
double asqrt(double);
double aatan2(double, double);

PROJVALUE PROJ_DLL pj_param(PJ_CONTEXT *ctx, paralist *, const char *);
paralist PROJ_DLL *pj_param_exists(paralist *list, const char *parameter);
paralist PROJ_DLL *pj_mkparam(const char *);
paralist *pj_mkparam_ws(const char *str, const char **next_str);

int PROJ_DLL pj_ell_set(PJ_CONTEXT *ctx, paralist *, double *, double *);
int pj_datum_set(PJ_CONTEXT *, paralist *, PJ *);
int pj_angular_units_set(paralist *, PJ *);

paralist *pj_clone_paralist(const paralist *);
paralist *pj_search_initcache(const char *filekey);
void pj_insert_initcache(const char *filekey, const paralist *list);
paralist *pj_expand_init(PJ_CONTEXT *ctx, paralist *init);

void *free_params(PJ_CONTEXT *ctx, paralist *start, int errlev);

double *pj_enfn(double);
double pj_mlfn(double, double, double, const double *);
double pj_inv_mlfn(double, const double *);
double pj_qsfn(double, double, double);
double pj_tsfn(double, double, double);
double pj_msfn(double, double, double);
double PROJ_DLL pj_phi2(PJ_CONTEXT *, const double, const double);
double pj_sinhpsi2tanphi(PJ_CONTEXT *, const double, const double);
double *pj_authset(double);
double pj_authlat(double, double *);

COMPLEX pj_zpoly1(COMPLEX, const COMPLEX *, int);
COMPLEX pj_zpolyd1(COMPLEX, const COMPLEX *, int, COMPLEX *);

int pj_deriv(PJ_LP, double, const PJ *, struct DERIVS *);
int pj_factors(PJ_LP, const PJ *, double, struct FACTORS *);

void *proj_mdist_ini(double);
double proj_mdist(double, double, double, const void *);
double proj_inv_mdist(PJ_CONTEXT *ctx, double, const void *);
void *pj_gauss_ini(double, double, double *, double *);
PJ_LP pj_gauss(PJ_CONTEXT *, PJ_LP, const void *);
PJ_LP pj_inv_gauss(PJ_CONTEXT *, PJ_LP, const void *);

const struct PJ_DATUMS PROJ_DLL *pj_get_datums_ref(void);

PJ *pj_new(void);
PJ *pj_default_destructor(PJ *P, int errlev);

double PROJ_DLL pj_atof(const char *nptr);
double pj_strtod(const char *nptr, char **endptr);
void pj_freeup_plain(PJ *P);

PJ *pj_init_ctx_with_allow_init_epsg(PJ_CONTEXT *ctx, int argc, char **argv,
                                     int allow_init_epsg);

std::string PROJ_DLL pj_add_type_crs_if_needed(const std::string &str);
std::string pj_double_quote_string_param_if_needed(const std::string &str);

PJ *pj_create_internal(PJ_CONTEXT *ctx, const char *definition);
PJ *pj_create_argv_internal(PJ_CONTEXT *ctx, int argc, char **argv);

// For use by projinfo
void pj_load_ini(PJ_CONTEXT *ctx);

// Exported for testing purposes only
std::string PROJ_DLL pj_context_get_grid_cache_filename(PJ_CONTEXT *ctx);

// For use by projsync
void PROJ_DLL pj_context_set_user_writable_directory(PJ_CONTEXT *ctx,
                                                     const std::string &path);
std::string PROJ_DLL pj_get_relative_share_proj(PJ_CONTEXT *ctx);

std::vector<PJCoordOperation>
pj_create_prepared_operations(PJ_CONTEXT *ctx, const PJ *source_crs,
                              const PJ *target_crs, PJ_OBJ_LIST *op_list);

int pj_get_suggested_operation(PJ_CONTEXT *ctx,
                               const std::vector<PJCoordOperation> &opList,
                               const int iExcluded[2], bool skipNonInstantiable,
                               PJ_DIRECTION direction, PJ_COORD coord);

const PJ_UNITS *pj_list_linear_units();
const PJ_UNITS *pj_list_angular_units();

void pj_clear_hgridshift_knowngrids_cache();
void pj_clear_vgridshift_knowngrids_cache();
void pj_clear_gridshift_knowngrids_cache();

void pj_clear_sqlite_cache();

PJ_LP pj_generic_inverse_2d(PJ_XY xy, PJ *P, PJ_LP lpInitial,
                            double deltaXYTolerance);

PJ *pj_obj_create(PJ_CONTEXT *ctx, const NS_PROJ::util::BaseObjectNNPtr &objIn);

/*****************************************************************************/
/*                                                                           */
/*                              proj_api.h                                   */
/*                                                                           */
/*    The rest of this header file includes what used to be "proj_api.h"     */
/*                                                                           */
/*****************************************************************************/

/* pj_init() and similar functions can be used with a non-C locale */
/* Can be detected too at runtime if the symbol pj_atof exists */
#define PJ_LOCALE_SAFE 1

#define RAD_TO_DEG 57.295779513082321
#define DEG_TO_RAD .017453292519943296

extern char const PROJ_DLL pj_release[]; /* global release id string */

/* procedure prototypes */

PJ_CONTEXT PROJ_DLL *pj_get_default_ctx(void);
PJ_CONTEXT *pj_get_ctx(PJ *);

PJ_XY PROJ_DLL pj_fwd(PJ_LP, PJ *);
PJ_LP PROJ_DLL pj_inv(PJ_XY, PJ *);

PJ_XYZ pj_fwd3d(PJ_LPZ, PJ *);
PJ_LPZ pj_inv3d(PJ_XYZ, PJ *);

void pj_clear_initcache(void);
void PROJ_DLL pj_pr_list(PJ *); /* used by proj.cpp */
char *pj_get_def(PJ *, int);
int pj_has_inverse(PJ *);

char *pj_strdup(const char *str);
const char PROJ_DLL *pj_get_release(void);
void pj_acquire_lock(void);
void pj_release_lock(void);

bool pj_log_active(PJ_CONTEXT *ctx, int level);
void pj_log(PJ_CONTEXT *ctx, int level, const char *fmt, ...);
void pj_stderr_logger(void *, int, const char *);

int pj_find_file(PJ_CONTEXT *ctx, const char *short_filename,
                 char *out_full_filename, size_t out_full_filename_size);

// To remove when PROJ_LIB definitely goes away
void PROJ_DLL pj_stderr_proj_lib_deprecation_warning();

#endif /* ndef PROJ_INTERNAL_H */
